This invention is related to automatic steering apparatus employing control means for detecting the direction of rotation of a compass member to determine the difference between a selected compass direction and the actual boat heading, to provide a compensating signal to a steering actuator, and more particularly to an apparatus for controlling power between a power source and the actuator with means for detecting the direction of rotation of a drum and counting the number of light-absorbent and light-reflective areas along the surface of the drum as the boat's heading deviates with respect to a given compass heading.
Some conventional automatic steering apparatus for boats and the like employ an optical device that senses the relative motion between a flat compass disk and the boat in such a manner as to automatically energize a steering member to compensate for the error in boat heading. Conventional units have considerable hunting and are somewhat insensitive to slight changes in course. Usually the disk and the light source must be mechanically repositioned when the boat's course is changed.